IELTS Speaking module 3 is going to last for 5 minutes, and the examiner will ask some follow-up questions relating to the topic which was given in the speaking module part 2.  The examiner is mostly interested in your opinion regarding an issue. The examiner might ask for your viewpoint.
The IELTS Speaking part 3 is analogous to a press-conference where a journalist asks questions from the speaker. You should not think that the examiner is going to put you under some kind of pressure as a matter of fact the examiner will be extremely polite to you at all times.